Verified answer

It really depends, and this is where a store keeper in Toronto (I believe Toronto) recently got into trouble. In that case the store keeper saw someone he thought was shop lifting from his store. The guy left and the store keeper reviewed the video tape and confirmed the guy was stealing. Now, as a police officer, unless I witness the guy stealing first hand I cannot arrest him. Our criminal code differentiates between offences that are "arrestable" and those that are not. If it is not an arrestable offence then the police officer can only issue an "Appearance Notice" which is a form letting someone know they are being charged with an offence and that they must attend court on a certain date.

Anyway, in the case of our store keeper he happened to see the guy again later that afternoon, he chased him down and held him for about 5 minutes till the police showed up. He in effect did a citizens arrest BUT he ended up being charged for assault (it could have been kidnapping really) because he didn't have the authority to arrest the guy for the offence that he did not witness first hand and act upon at that time.

So, long story short, IF you observe someone committing a crime AT THE TIME, then you can effect a citizens arrest AT THE TIME. To do so at any other time is unlawful and you could be held liable yourself.

Another thing to consider is that when I, as a cop, arrest someone if they resist or if I get injured then I'm covered both for my lawful actions and any injuries. You, if you do a citizens arrest and the guy fights you so that you are injured, are on the hook for your injuries and if you can't work....too bad, so sad. Your insurance isn't going to cover you.

Lots to think about and it's not as cut and dried as people may like it to be. The attitude of "Oh yeah, I can do a citizens arrest on someone" can cause you lots of problems. Well, not YOU personally but who ever does it.

Yes, but you have to have a legit reason and you have to read them their rights and contact authorities as soon as possible. When a security guard arrests someone they are actually preforming a citizens arrest.